Optics & Snell's Law

• What are the two angles in this Snell's Law diagram?

  A) i

  B) r

  
• The gradient of a sin(i) / sin(r) graph is the refractive index of the medium
• GCSE Snell's Law equation: $\frac{sin(i)}{sin(r)}$ = n (Refractive index of material)
• The Snell's Law equation states that $n_1 sin(\theta_1) =$$n_2 sin(\theta_2)$ where $n_1$ = the refractive index of the first material, $\theta_1$ is the angle of incidence, $n_2$ = the refractive index of the second material and $\theta_2$ = the angle of refraction
• When the angle of refraction is greater than the Critical angle, Total Internal Reflection Occurs.
• The critical angle is the minimum angle where Total internal reflection occurs
• Sin(C) = $\frac{1}{n}$
• When the angle of refraction is 90º (Parallel with the line between the two mediums), the angle of incidence is the Critical Angle
• The focal length is the distance between the lens and the focal point
• The focal points are equidistant from the lens
• The object distance (u) is the distance between the object and the lens
• The image distance (v) is the distance between the lens and the image
• There are three rays on a converging lens ray diagram:

  1. starts parallel to the principle axis and comes out through focal point
  2. Goes straight through the centre of the lens
  3. Goes through the focal point and then comes out parallel to the principle axis
• in a single converging lens diagram, the image that is produced is real, diminished and inverted
• When V = 2f, U = V
• f = the focal length
• magnification = image height/object height
• magnification = U/V